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2.
GRADING January 2005200 GENERALNormally, the first stage of roadway construction is clearing and grubbing of the roadway area. The Inspectorshould review the Project Plans, Standard Specifications, and Special Provisions covering this phase and makecertain that the work is performed as required. Particular attention should be given to keeping the Contractorsactivities confined within the limits of the slope stakes. The disposal of the resulting materials should be asdirected in the contract documents. However, if disposed of off site, a letter granting permission should be in theproject files.The Resident Engineer and Inspector should be thoroughly familiar with the Project Plans and SpecialProvisions, soil profile, all right-of-way (ROW) agreements, and borrow pits before grading operations arestarted. Together, the Resident Engineer (RE) and Inspector should make a plans-in-hand inspection of theproject noting the following: • clearing limits shown on the Project Plans versus clearing actually needed; • typical sections shown on the Project Plans; • soil profile, cut slopes, and shrink and swell factors indicated; • drainage profiles (check that existing drainage has not changed, proposed drainage does not • flow off the right-of-way, and natural drainage isnt changed to adversely affect landowners or • structures upstream and downstream); • utilities, fences, or other obstructions to be moved or protected; • private property boundaries and other restricted areas; • vegetation, survey monuments, archaeological sites, or other physical features to be protected, • preserved, or relocated; • borrow sources and access roads; • unusual soil/moisture conditions such as springs, seeps, or swamps; • construction traffic control requirements; • subgrade/embankment stabilization requirements; and • ROW infringements or unresolved ROW agreements.As noted above, the Resident Engineer should inspect the drainage of lands adjacent to the highway and makecertain that all drainage structures, inlets, outlets, channel, and dikes are properly located. The ResidentEngineer should determine the need for any additional drainage facilities.Special care should be given to locations of material sources in streambeds. The impact of changes in thestream flow conditions on structures and other developments must be carefully considered. Impacts can extenda considerable distance from the point of disturbance so it is often necessary to consult with the hydraulicsspecialists before approving work in streambeds.Highway construction projects have been identified as one of the primary sources of soil erosion andsedimentation. Construction of highways typically disturbs large areas of natural vegetation that can result in anaccelerated rate of soil erosion. During the course of the grading and draining, frequent inspections should beperformed to determine that the sequence of operations is such that damage to any of the work will be kept to aminimum in case of heavy rains (see Subsection 104.09).For roadway excavation, the Inspector should review the soil profile while inspecting the work and should noteradical variations in the actual soil conditions compared with those on the soil profile. Major differences in thesoils encountered from those indicated could justify changes in the design. Should wide differences be found, itwould be advisable to request a review of the conditions by the Materials Group. This is especially critical atConstruction Manual 200 - 1

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GRADING January 2005finish subgrade elevation. The plasticity index (PI) and amount passing the #200 (75µm) sieve of the finalsubgrade material are checked against the design values to determine whether adjustments to the pavementstructural section are necessary. This must be done as soon as possible since any increase in pavementsection could mean extra surveying and additional work by the Contractor, both may have an impact on theContractors schedule. (See Subsection 203-3.03(D), Unsuitable Materials.)For embankment construction, the entire subgrade must be proof rolled with a loaded water truck or any otherheavy piece of equipment. The Inspector should see that any unstable spots in the natural ground are correctedbefore any embankment lifts are placed.The Inspector must be familiar with the location of approved borrow pits and the quantity and quality of materialsto be removed.The Inspector is responsible for seeing that the grade is constructed in accordance with the Project Plans to thelimits indicated by the slope stakes. If there is any question concerning the placement or markings of a slopestake, the Inspector should contact the Contractor’s survey party chief for clarification.Construction of DetoursMany construction projects require detours prior to building the roadway. Usually, the need for such detours isforeseen, and detailed information about detour construction is given in the Project Plans or referred to in theStandard Drawings. An on-site inspection of all proposed detours should be made. Any recommendations thatmight serve to add to the safety of the traveling public should be referred to the Resident Engineer.When changes are made to the detours shown on the Project Plans or new detours are added, the changes areto be reviewed by the Regional Traffic Engineer and documented by change order.The Department recognizes its obligation to provide safe, easy-to-drive detours. This, along with minimal delay,is a benefit to our public relations.Proper signing, marking, and lighting of detours are extremely important. All detours should be signed andmarked as directed in Part IV of the MUTCD with the ADOT Supplement.After the completion of detour construction including signing, striping, and lighting, the Resident Engineer shouldmake a daytime and nighttime inspection of the detour. The traffic control coordinator for the project should dofrequent re-inspections and documentation of the detour.It is beneficial to have someone who is not involved in the design of traffic control accompany the ResidentEngineer during his or her inspection of traffic control. An independent observation can be very beneficial infinding problems. Arrange to drive through the project with a local police officer, county deputy, or Department ofPublic Safety officer. Deficient detour conditions must be remedied as soon as possible. There may beinstances when the Contractors work will need to be suspended until detour safety is satisfactory.A complete record including diagrams, plans, photographs and/or video recordings must be kept showing alltraffic control devices and the detour including any changes to either. Plans and diagrams should show the type,location, and sizes of all signs, barricades, and any other traffic control device. The photographs and videorecordings should be taken to provide a sequence of pictures showing the detour from beginning to end.Construction Manual 200 - 2

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GRADING January 2005201 CLEARING AND GRUBBING201-1 DescriptionNormally this operation is the first phase of construction. It consists of clearing the area within the project limitsof all obstructions and vegetation in accordance with the specifications prior to commencing any earth-movingactivity. During the clearing and grubbing operations, care should be taken to limit the activity of the Contractorto an area within the slope stake boundaries as much as possible. The intent is to preserve as much vegetationoutside the slope stake limits as possible. When clearing limits are staked by the Contractor, care must be takento assure the slope rounding details in the Standard Drawings are followed and the additional distance for sloperounding is cleared.When the Contractor provides a material source, plant site, or equipment yard, he or she will be required toprepare an environmental analysis addressing the usage (refer to Subsections 107.11 and 1001-4). In addition,the Contractor must notify the Arizona Commission of Agriculture and Horticulture prior to any clearing operation.The purpose of this notice is to provide the opportunity for salvage and preservation as provided in the ArizonaNative Plant Law. The Resident Engineer should bring these requirements up at the preconstruction conferenceif it is applicable to the project. This applies to privately owned land as well as publicly owned land.Environmental conditions often restrict operations in watershed areas.The Standard Specifications provide for saving all trees and shrubs found suitable for roadside improvement andbeautification if they will not interfere with construction. In order that the Contractor might know which trees andshrubs are to be saved, the Resident Engineer (with the assistance of one of ADOT’s Landscape Supervisors)shall mark such trees and shrubs in a distinguishable manner. The Contractor should be informed of thismarking.When sufficient clearing and grubbing has been done to permit the start of grading operations, an inspection ofthe area shall be made and, if found acceptable, the Contractor can be allowed to proceed.201-3 Construction Requirements201-3.02 Removal and Disposal of MaterialsDisposition of cleared materials requires careful attention. All cleared and grubbed material must be removedand disposed of before earthwork operations can begin.The Standard Specifications provide that all debris from the clearing and grubbing operations shall be removedfrom the project and disposed of. All disposal is to be made outside of the right-of-way, and the Contractor mustobtain written permission from the land owner (not the tenant) for such use of the land. A copy of such writtenconsent must be given to the Resident Engineer.The use of any disposal site and haul roads, public or private, may require an Environmental Analysis. TheResident Engineer should carefully inspect disposal sites to judge the impact such use will have on thesurrounding property. Remember that impacts of activities off the project can be in conflict with the projectenvironmental analysis on which the project approval is based.Construction Manual 201 - 1

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GRADING January 2005201-5 Basis of PaymentClearing and grubbing may be paid for as a lump sum or by the area. Measurements of the actual areas to becleared should be made before the clearing operation begins. Quantities should be computed and theContractor advised so that a verification of the quantity can be made if required before the area is disturbed.If clearing and grubbing are not paid for directly, the clearing limits should still be documented.Construction Manual 201 - 2

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GRADING January 2005202 REMOVAL OF STRUCTURES AND OBSTRUCTIONS202-3 Construction Requirements202-3.01 GeneralThis work consists of the removal and satisfactory disposal of all buildings, fences, structures, old pavementsoutside the slope staked areas, abandoned pipe lines, and any other obstructions that are not designated orpermitted to remain, unless they are covered by another portion of the contract. Normally, the items to beremoved under this section are indicated under the miscellaneous removal item of the contract. Salvageablematerial that will be retained by the Department should be removed with care and inventoried in order topreserve its usefulness. Complete the “Receipt For Salvaged Materials” form to document salvaged materials.Before any removal work begins, a value should be established for each of the removed items. This isnecessary to properly document the amount of work performed as a percentage of the pay item in the contract.The Resident Engineer and the Contractor should mutually agree upon the value. Blue Stake the area todetermine exact location of underground utilities that may conflict with removal items.It is recommended that a photographic or videotape log of all existing conditions on the project be establishedbefore work commences. This can be a valuable record of existing conditions.All items to be removed, listed or unlisted in the Project Plans and Special Provisions, should be documented toshow what was removed and when the removal was accomplished.When the natural ground is disturbed by the removal of structures and obstructions, all depressions are to berefilled and compacted according to Standard Specifications before any embankment is placed over the area.Construction Manual 202 - 1

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GRADING August 2009203 EARTHWORK203-2 GeneralAn excellent description of construction equipment can be found in the Caterpillar Performance HandbookThe inspector should check the Special Provisions for pre-wetting requirements when cuts are deeper than 3feet (1 meter). The inspector should review subsection 206-3 of the Standard Specifications when the contractordecides to pre-wet pay items that will be measured and paid on the basis of weight.203-2.02 Contractor Quality ControlWhen the Special Provisions require that the Contractor perform quality control, the Contractor will beresponsible for quality control measures necessary to provide acceptable quality in the production, hauling, andplacement of materials.203-3 Roadway ExcavationRoadway excavation involves loosening, digging, loading, hauling, placing, compacting, finishing, and disposal ofthe excess materials in the roadway cut sections as specifically described in the Standard Specifications andSpecial Provisions. Before beginning this operation, the Resident Engineer should have a discussion with theContractor on the removal and disposition of material excavated from specific areas within the project. Thereshould be an agreement as to the placement of excavated materials.203-3.03 Construction Requirements(A) GeneralThe Standard Specifications do not allow payment for materials excavated beyond the limits of the roadway,except in certain instances. If at any time the Contractor excavates outside the slope stake limits, below finishedsubgrade elevation, gouges, or undercuts slopes (except as required by the Project Plans), the Contractor shallbe notified in writing that this material will not be paid for. When the Contractor excavates outside the requirelimits, the material will be replaced with a material of equal or better quality and compacted to an acceptabledensity at the Contractor’s expense.Undercutting below subgrade elevation might be ordered for the purpose of correcting an unstable condition,diverting water, or providing a more gradual change from cut to fill. Observation of numerous fill settlements inareas of abrupt changes indicates a need for undercutting at these locations. Other problems at grade cut pointsare caused by topsoil being an inferior subgrade material.Any undercutting which the Resident Engineer has authorized should be measured for payment as roadwayexcavation unless there are extenuating conditions that warrant performance of the work as extra work. (SeeSubsection 109.04). However, if the undercutting was the result of the Contractor’s operation, no additionalpayment should be made.Before the work is accepted, the roadway section affected by such undercutting shall be corrected to true plansgrade and section.Construction Manual 203 - 1

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GRADING August 2009In cut sections, cut ditches may be constructed to prevent the pooling of water. The outlet ends of these ditchesshould be constructed so that the water will be discharged onto natural ground and not against the embankmentslope. Cut ditch sections are staked in conjunction with the roadway excavation.(B) SlopesThe Contractors selection of the type of equipment for finishing of slopes is predicated upon steepness, access,and type of material.Rounding of slopes at the top and ends of cut sections are normally done as the excavation progresses,because of more ready access to those areas. Slopes should be trimmed and shaped as much as possibleduring the progress of the excavation operation.Slope rounding is not always shown on the typical roadway section in the Project Plans since the typical sectionrefers to Standard Drawings that do specify slope rounding.There are some instances where slope rounding is not required. These areas are usually described in theProject Plans or Special Provisions.(C) Blasting(1) GeneralOvershooting, or blasting which loosens solid rock formations outside the limits of the planned slopes, maycause slides and overbreakage. The Contractor can avoid overshooting by plotting the depth and direction ofthe drill holes and determining their relation to the slope line to ascertain that they are not beyond the slope line.The Contractor should evaluate the amount and type of explosive and the spacing of the holes. The ResidentEngineer should closely observe the drilling and shooting operations. If the method used results in overshootingor damage to the adjacent property, the Contractor should modify the blasting plan. The Resident Engineer willnot assume responsibility for the Contractors methods or procedures, but should become familiar with theproperties, uses, and action of explosives and detonators used by the Contractor. ADOT Geotechnical Servicesmay be contacted for technical assistance. Each project office located on a job where blasting will be doneshould obtain information pertaining to the use and safety of commercial explosive material. Refer to theReference and Additional Information section at the end of this chapter for publications available.The Resident Engineer should see that good records are kept of blast hole patterns, loading rates, types ofblasting agents used, and comments on the results of the blast. Did it throw a lot of rock outside the slopes; wasthere overbreakage, etc.? Good records of the blasting operations are often useful in resolving disputes aboutoverbreakage and alleged changed conditions.If blasting is near a developed area, a joint inspection should be made of the surrounding properties prior toblasting to assist in verifying any damage which may occur from the blasting. Photographs or a video recordingof the area during this inspection should be made.It is very important that the Resident Engineer review the blasting plan to ensure that the Contractor has followedall requirements for a blasting permit. All required permits must be obtained prior to any blasting.(2) Controlled BlastingThe Contractor shall provide a written blasting plan prior to beginning any blasting work. This plan must bereviewed by the Resident Engineer to verify it contains the following minimum requirements:Construction Manual 203 - 2

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GRADING August 2009 • the method for transporting the blasting agent to the site; • the type of blasting agent used; • the size and depth of holes; • size and loads of blast pattern; • type of stemming material; • ignition source; • method of storage on site; • procedures in case of a misfire; • type of firing device (electrical, etc.); • type of security that will be used; and • name of blasting company or person doing the blasting, and copies of their certifications or license with issuing agency.The Inspector should review all requirements for transporting and storage of the blasting agent and review theContractor’s operation for compliance.In an attempt to control the fracture of the rock along the slope line, presplitting is often required on many rockcuts. Presplitting or preshearing can be defined as the establishment of a free surface or shear plane by thecontrolled use of explosives and blasting accessories in appropriately aligned and spaced drill holes.Preshearing involves a single row of holes drilled along the neat excavation slope line. Presplitting involves aseries of charges fired simultaneously in adjoining holes. Collision of the shock waves between holes places theweb between the holes in tension and shears the rock between the holes. With proper hole spacing and chargeto suit the type of material being blasted, the fracture zone between the holes will be a narrow sheared areathrough which the subsequent primary blasts can break.The presheared plane reflects some of the shock waves from the primary blasts that follow, which prevents themfrom being transmitted into the finished wall and minimizes shattering and overbreak.(3) Radio Frequency HazardsRadio Frequency (RF) transmitters, which include AM and FM radio, cellular phones, television, and radar,create powerful electromagnetic fields, decreasing in intensity with distance from the transmitter antenna. If theelectric detonator wires are in a strong RF field (near a transmitter that is radiating RF power) the unshielded legwires or circuit wires, whether connected to a blasting machine or not, will act as an antenna similar to that on aradio or TV set. The RF field will induce electric current in the circuit wiring that will flow through the electricdetonator connected to it and sufficient RF energy may be induced in the wires to fire the electric detonator.Tests have demonstrated that electric detonator wires, under certain circumstances, may pick up enough electricenergy from such fields to cause them to explode.Commercial Amplitude Modulated (AM) transmitters are potentially the most dangerous. They combine highpower and low frequencies so that there is little loss of RF. Low frequencies induce more current than highfrequencies so the potential to induce a current in the blasting wire is high.Frequency-Modulated (FM) and TV transmitters are unlikely to create a hazardous situation. Although theirpower is extremely high and antennas are horizontally polarized, the high frequency currents are rapidlyattenuated in detonators or lead wires. Also, these RF sources usually employ antennas on top of high towersand this has an additional effect of reducing the electromagnetic field at ground level.Mobile radio transmitter units must be rated as a potential hazard because they enter directly into the blastingarea. The Citizen Band radio is an unusual problem for several reasons.Construction Manual 203 - 3

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GRADING August 2009 1. There are millions of units being used by the general public. 2. The operating frequency of these units is in the range that is considered to be the worst case for typical electric blasting circuits. 3. Some irresponsible operators use illegal linear amplifiers to increase their power output.Federal regulations require the posting of signs within 1000 feet (300 meters) of construction sites warning thattwo-way radios should be turned off because of blasting. Observance of the posted signs will provide thenecessary degree of safety if the units are operating within the legal power output. Exhibit 203-3.03-1 showstables of distances designed for the convenience of the commercial blaster. The selected groupings include allthe obvious types of RF transmitters that may be encountered around blasting areas.The safe distances recommended are for the FCC approved units; it is not possible to specify safe distances forthe illegal units because they do not operate within any limits. When planning to blast electrically at a newlocation, the Resident Engineer should inspect the area for RF transmitters before blasting is started and followthe recommendations of Exhibit 203-3.03-1.Construction Manual 203 - 4

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GRADING August 2009There may be instances where the use of two-way radios will increase the overall safety of a blasting operationby providing instant communication. When radios are used for this purpose, the minimum separations specified,in Exhibit 203-3.03-1 for a particular transceiver, should be maintained.Due to static electricity, firing of explosives should not be carried out during a thunderstorm or when one isapproaching. During such a period, leading wires should be short-circuited and all persons should move to asafe distance. Short-circuiting is a safeguard; however, it may not prevent the firing of a charge if the wires arestruck by lightning.Safety should be the concern of all individuals in the blasting area. Shattered windows, flying boulders, movedrailroad tracks, damaged forest and highways, and injured people could be the result of a poor blastingoperation. Blasting is an extremely dangerous activity, and the Contractor must have the proper respect for thehavoc that negligence or errors can cause. Before blasting, the Contractor should inform the local lawenforcement agencies, inform neighbors in the area, post "Blasting Ahead—Turn Off 2-Way Radio" signs,purchase necessary permits, and use necessary personnel to cordon off the area.The ADOT Safety and Health Section can assist in resolving safety issues related to blasting. In addition, eachproject office should have a current copy of the OSHA Safety and Health Standards for the ConstructionIndustry.(D) Unsuitable MaterialsUnsuitable materials are defined as those materials that may adversely affect the stability of the roadbed. Anysoils that may cause instability or have some other detrimental effect should not be used unless adequatelytreated to make them satisfactory. If unsuitable materials are encountered, they should be removed andreplaced with acceptable material, or should be processed and placed in a manner that will make the materialacceptable.The design of a pavement structure is influenced by many variables. One of the most important variables is thestrength of the subgrade soils. Our present design method characterizes the subgrade soils by use of the "R"value test, or Resilient Modulus. In the AASHTO Test Manual, the "R" value test method is described as a"procedure for testing both treated and untreated laboratory compacted soils or aggregates with the stabilometerand expansion pressure devices to obtain results indicative of performance when placed in the base, subbase,or subgrade of a road subjected to traffic loads." The "R" value test takes three days to complete and requiresspecialized equipment. For that reason, all the "R" value tests are performed by the Materials Group. For designpurposes, the design "R" value is determined from calculated "R" values, using the Plasticity Index (PI) and thepercent passing the #200 (75μm) sieve (PC) of the subgrade materials as well as from actual "R" value tests.Using this PI and material passing the #200 (75μm) sieve (PC) information, a subgrade acceptance chart isdeveloped (an example is shown Exhibit 203-3.03-2). This chart is used to determine whether the subgrade issuitable for the proposed design. The subgrade acceptance chart is included in the Final Materials DesignReport distributed to the District and the project. When borrow is required to construct subgrade, the projectSpecial Provisions will include the equation, “PC+(2.83xPI) shall not exceed XXX”, to determine its acceptabilitybased on the PI and PC. If the chart or formula is not available at the District, a copy may be obtained bycontacting Materials Group, Pavement Section.Construction Manual 203 - 6

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GRADING August 2009If during subgrade acceptance testing (other than borrow), the PI and materials passing a #200 (75μm) sieve ofthe sample fall within the unacceptable region of the subgrade acceptance chart, Materials Group should becontacted. The design may be affected by these results, necessitating a redesign of the pavement structuralsection. Meanwhile, efforts should be made to isolate the area of unacceptable material.Isolating the area of unacceptable material is normally done by sampling on each side of the unacceptablematerial in increments of 100 feet (30 meters) until acceptable samples are obtained. Using this information,Materials Group will determine the best method of dealing with the unacceptable subgrade material.If borrow material fails to meet the requirements of the formula, the Contractor will be required to locate anothersource of borrow.Subgrade acceptance samples will normally be taken from the upper 3 feet (1 meter) of subgrade. In certaincircumstances the sampling will extend to a greater depth if the conditions could affect the structural design.(E) Surplus MaterialSome projects may have an excess of excavated material after the required embankment work is completed. Ifthis is known beforehand, a designated disposal site may be provided on the Project Plans. If no designateddisposal site is provided, then it becomes the responsibility of the Contractor to provide an acceptable means ofdisposing of this material. The Resident Engineer may approve of disposing of this excess material within theproject limits. If the Contractor intends to provide a disposal site, an Environmental Analysis may be required.When left to remain on the project, surplus material should be used in widening embankments, constructingberms, emergency turnouts, view points, and dikes. If a large amount of waste appears to be developing due toerrors in estimating shrinkage and swell factors or for any other cause, the District Engineer should be notified assoon as possible so that necessary steps may be taken for proper disposal of the surplus material. Unsightlywaste piles of surplus material should not be allowed.Waste material that is used for roadway items such as widening embankments, widening berms, turnouts,viewpoints, dikes, etc., will be placed in accordance with Specification 203-10. End dumping over the side of afill will not be allowed. Widening of fills from the top will cause the fill to be unbalanced—a condition that cancause the fill to slide or crack from the unequal loading. This type of failure becomes more severe on steep sideslopes.Material shall not be wasted without the permission and direction of the Resident Engineer. When working withinUS Forest Service lands, US Forest Service officials must approve waste sites.203-4 Drainage ExcavationIt is important that much consideration be given to adequate drainage around and through the roadway prism.Expenditure for drainage control may prove to be well justified due to potential maintenance savings andprotection of adjacent properties.Evaluate not only what condition exists, but also what might occur during the life of the project. Bank protectionis often overlooked when evaluating drainage channels, as is nearby urban development. Urban developmentreduces natural ground surface area, which dramatically increases precipitation runoff. Possible scour orerosion of streambeds is very important in determining proper grades for construction of bank protection. Alwaystry to plan drainage so that no abrupt directional changes are made, but rather gradual changes that will allowthe water to run its course with minimal erosion.Construction Manual 203 - 8

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GRADING August 2009Occasionally, properly engineered drainage will require work outside of the established right-of way. In suchcases, additional drainage easement areas or construction easements will have to be secured from the ADOTRight-of-way Group.Detailed staking of drainage work is required to ensure "puddling" does not occur on abutting private property.This is especially important in developed areas.Channel changes that will direct the flow into a drainage structure should be completed by the time the structureis completed. To minimize embankment damage during construction, channel changes for the purpose ofdirecting the water flow away from the roadway section should be constructed before completion ofembankment. Adequate protection should be provided to prevent erosion due to diversion of water through newchannels.When failure to complete the needed channels and dikes endangers the work or other property, the Contractorshould be notified in writing. The condition should be well documented and photographed when the Contractordoes not take timely action to correct the situation.Inlet or outlet channels to culverts should present a neat appearance upon completion and should be open andready for use upon completion of the structure. The Contractor is responsible for any damage and repairnecessary due to inlets and outlets at structures not working properly.Inspection of Drainage FacilitiesAfter completion of all drainage structures, drainage ditches, and channels, the Resident Engineer should makean inspection of the entire project for the purpose of locating any areas where water might collect. If such areasare encountered, the necessary corrections should be made. Rainstorms during construction afford an excellentmeans of checking the adequacy of constructed drainage. Take advantage of them.203-5 Structural Excavation and Structure Backfill203-5.03 Construction Requirements(A) ExcavationIn most types of soil it is necessary to provide shoring, or slope the ground beyond the neat lines shown in theProject Plans or Standard Drawings in order to avoid caving. The contractor’s slope, shoring and trenching planmust be approved by the Resident Engineer. Side slopes must conform to the Occupational Safety and HealthAdministration (OSHA) standards. Therefore, all excavations will automatically be referred to the OSHAStandards for excavation. It is very important that the Inspector have a copy of the latest OSHA Standards forexcavation when working in these areas. See Subsection 501-3 of this manual for a discussion of OSHAStandards for trenching.When plans indicate the structure is to rest on rock, then excavate to a depth sufficient to expose sound material.The rock surface shall be rough, and approximately level, or stepped. Rock seams should be pressure grouted.It is essential that the subgrade foundation under a structure be uniform and firm under the entire bearingsurface. When unsuitable material is at the excavation planned grade then it must be removed and replacedwith structure backfill material. When a portion of the structure is on yielding material and the other portion is onunyielding material, or rock then remove the rock to a minimum depth of 2 feet (0.6 meter) below grade, andreplace with structure backfill material in accordance with Specification 203-5.03(B). If it can be avoided,Construction Manual 203 - 9

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GRADING August 2009culverts should not be placed partly on filled ground and partly on undisturbed natural ground because of theprobability of unequal settlement. If any portion of a culvert must be placed on filled material, the filled materialshould be placed in accordance with Specification 203-10 Embankment Requirements.When concrete is to be placed on material other than rock, special care must be taken not to disturb the bottomof the excavation. When suitable material in the bottom of the excavation is disturbed or over excavated, thatportion of the foundation shall be restored by the contractor in accordance with Specification 203-5.03 (B) to afirm foundation without payment.(B) BackfillSpecification 203 permits the Contractor some latitude in selecting the material while still requiring a material thatis free of frozen lumps, chunks of clay, or other objectionable material, and conforms to gradation, plastic index,and resistivity requirements.The material should be placed in layers not to exceed 8 inches (200 millimeters) in depth before compaction. Itis advisable to mark the wall or area being compacted in 8 inch (200 mm) increments as each lift is placed inorder to assure proper lift thickness. Care should be taken to extend the compacted area as far as necessary inorder to notch into firm material.The Standard Specifications require cutting into compacted material both laterally and longitudinally, with allmaterial to be compacted.The minimum frequency of density testing should be in accordance with the Sampling Guide in the MaterialsTesting Manual. At the start of operations on a project, it is advisable to perform more frequent tests to evaluatethe effectiveness of compaction methods, material, and moisture content, as well as the variability of the entirebackfill and compaction process. The tests should be timely so that there is a minimum of delay to theContractors operations.Backfill material should not be placed adjacent to a concrete structure until the concrete has developed theminimum strength specified for that structure. Standard requirement is a minimum compressive strength of2,000 PSI (15 MPa) and in no case backfill before 72 hours after casting. Field cure cylinders and strengthhistory are the basis for determining compressive strength. When placing backfill material around concretestructures care must be taken to bring the backfill material up uniformly on both sides of the structure. Backfillplacement on one side must never be more than 2 feet (0.5 meter) above backfill placed on any other side.Geocomposite Wall Drains conforming to Specification 1014-6 shall be installed on the soil side of abutmentwalls, wing walls, retaining walls, and culvert side walls. Care must be exercised to insure Geocomposite WallDrains are installed properly in accordance with Specification 203-5.03(C). If the drain fails to function properly itcould cause the structure to fail. There will be no measurement for payment of Geocomposite Wall Drains,unless specified otherwise.As an option the Contractor may use a slurry backfill material that conforms to the requirements of Specification203-5.03(B)(2). The slurry should be placed in uniform layers not to exceed 4 feet (1 meter) in depth beforecompaction. It is advisable to mark the wall or area being compacted in 4 foot (1 meter) increments as each liftis placed in order to assure proper lift thickness. The water content should not exceed 40 gallons per ton (150liters per metric ton) of backfill material. Internal vibrators should be used for compacting slurry in accordancewith Standard 601-3.03(D). Have the contractor excavate holes in the slurry so compaction can be tested atrandom depths. Direct the contractor to refill and compact test holes. Subsection 501-3.04 of this manual andthe Specifications have additional information on the applications and use of slurry backfill.Construction Manual 203 - 10

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GRADING August 2009203-5.04 Method of MeasurementThe pay limits for structural excavation and structure backfill are shown on the Standard Drawings (or in rareinstances, the Project Plans). These quantities are not meant to represent the actual quantity necessary tocomplete the work. Over excavation may be permitted, but no payment will be made for excavation due toslides, cave-ins, silting, or filling due to lack of side support, the action of the elements, or contractorcarelessness. No deduction will be made when the contractor elects not to excavate material within the paylimits, but excavation that does not extend to these limits should not be permitted if it interferes with the setting offorms and braces or the proper backfilling, compacting, and testing operations. Footings that must be overexcavated deeper than plan depth shall be measured as structural excavation up to 3 feet (1 meter) deeper thanthe Standard pay limit.203-6 & 203-7 Grader Ditch & Crown DitchesGrader ditches should be constructed as shown on the Project Plans or as directed by the Resident Engineer.Care as to size and general appearance should be exercised in the cutting of grader ditches. Ditchesconstructed through rock formations should be shaped and trimmed to leave a reasonably pleasing appearance.Grader ditches will be constructed to the length staked in the field, but it is often advisable to let an experiencedblade operator determine the alignment between stakes in order to provide proper drainage.A properly placed crown ditch or grader ditch may not ordinarily parallel the centerline of the roadway. Allditches should be constructed to approximate natural contour lines. When it becomes necessary to go beyondthe limits of the right-of-way to provide proper drainage, no work shall be performed off the right-of-way until theRight-of-way Group has obtained an easement. This need would normally be coordinated through the DistrictEngineer.203-8 Crown DikesCrown dikes are usually formed from material obtained from roadway, structural, drainage excavation, or borrow.The same precautions described in Section 203-6 should be considered in constructing crown dikes.Placing and finishing of crown dikes shall be as shown in the Project Plans or Standard Drawings.203-9 BorrowWhen the excavation does not develop enough material to complete the embankment, a borrow source may beprovided to make up the difference. The need for borrow is usually evident during the design phase, but maydevelop from unforeseen conditions.When borrow is required, it shall be obtained from approved sources in accordance with requirements ofSpecification 1001. One of the major factors affecting the acceptability of a borrow source is the requirementsplaced on the material by the structural design of the pavement. Requirements for borrow placed within the top3 feet (1 meter) of subgrade will be specified in the Special Provisions.Borrow is measured in the original, or final space it occupies depending upon the pay item description shown inthe contract. Borrow (Pit) items are measured in the original space occupied,Construction Manual 203 - 11

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GRADING August 2009whereas Borrow (In Place) is measure in the final space occupied. All roadway, drainage, or structuralexcavation shall be incorporated into the roadway embankment prior to the importing of borrow unless theResident Engineer has given written permission to the Contractor to do otherwise.There will normally be no payment for either roadway or structural excavation that is wasted when borrow hasbeen used, unless specified in the contract documents.On projects with Borrow (In-Place), or projects with over 5,000 cubic yards (3,800 meters cubed) of earthwork,the Resident Engineer should consult with the Roadway Designer or Project Manager to determine if the existingground line should be re-measured. The primary consideration should be reasonable accuracy and validity ofthe existing topographic information prior to beginning earthwork operations.If a question or disagreement regarding quantities arises, then additional measurements can be performedcovering that appropriate stage of construction. If there are no problems with quantities in the earthworkoperation, no measurement will be necessary beyond the initial work except for Borrow (In-Place).Arrangements to have aerial photography taken for the project should be made at least 30 days prior tobeginning any earthwork operation. If a survey crew can make remeasurement, the request should be madewith enough lead time to obtain the necessary crew. Borrow sources may need to be measured before and afterexcavation when borrow is used for miscellaneous purposes such as shoulder widening or flattening.Changes in borrow placement that result in: 1. a material with different properties being used; 2. a substitution for excavated material; or 3. a change from a specified source, are all changes to the contract requiring a supplemental agreement.Always remember written approval is required to change the borrow placement from that shown in the ProjectPlans.203-10 Embankment203-10.02 Embankment MaterialsIt is very important for the Inspector to ensure that no large rocks, boulders, broken concrete, or other largedebris are placed in areas where piling and drilled shafts are to be constructed (i.e., in embankment for a bridgeabutment). Subsection 203-10.02, and Subsection 203-10.03 limit the size and type of material that can beplaced in these areas. Subsection 203-10.03 includes all drilled shaft, metal pile, abutment, wing wall, andanchor slab locations. The same precautions should be taken at locations for guardrail, underground conduit,and light and signal pole foundations. Some projects build embankment for other projects, so the Inspectorneeds to be aware of other the impacts the Contractor’s embankment work could have on a future project.Steel H-piles will corrode in disturbed soils that have a low resistivity or an extreme pH value. Subsection 203-10.02 places limits on embankment soil resistivity and pH for that reason. The key to understanding thisspecification is that embankment soils are disturbed soils. An undisturbed native soil, which the pile is driventhrough, may have a resistivity and pH value outside the specifications. As long as the soil is undisturbed, it isusually not a problem for the pile. It is only disturbed soils used for fill, embankment and structure backfill thatthreaten a pile with long-term corrosion (refer to Subsection 203-5.03[B]).Construction Manual 203 - 12

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GRADING August 2009Two final points about piling and earthwork concern 1) the completion of all embankment work before pilingdriving begins (Subsection 603-3.04 [A]) and 2) the requirement of excavating to the top of the pile when theembankment has already been completed (203-5.03[A]). The first requirement is discussed further inSubsection 603-3.04 of this manual. The second requirement eliminates the risk of damaging or loosening of thepiles as a result of exposing, cutting, and removing excessive lengths of piling.203-10.03 Embankment Construction Requirements(A) PlacementEmbankment placed within top 3 feet (1 meter) of the finished subgrade elevation will have differentrequirements than embankment placed at greater depth. It is very important for the Inspector to ensure thatmaterial in the top layer meet all the standard requirements. Sampling and testing will be required in areaswhere embankment is covered by pavement or penetrated by bridge structures.The Contractor should not begin the removal and placement of borrow until all roadway, structural, and drainageexcavation has been removed and incorporated into the embankment, unless otherwise authorized by theResident Engineer.The long-term smoothness of a road depends to a large degree on the proper preparation of the area uponwhich the embankment is to be placed (the embankment foundation). The presence of slippage planes, areas ofunstable material, or water from irrigation, seepage, springs or just surface water retained in a clay basin, aresome of the detrimental conditions that may be encountered. The presence of localized areas of heavier, lushvegetation is an indication of the presence of water. Such areas should be investigated with consultation of theMaterials Group. If it is feasible, areas containing standing or running water should be removed, drained, orotherwise corrected before embankment is placed. In swamp areas where the subgrade is close to the groundline, it may be necessary to raise the grade. Corrective measures not included in the Project Plans or SpecialProvisions will require a supplemental agreement.If the existing ground surface is highly irregular, the surface should be smoothed or otherwise restored to areasonably regular surface.When constructing embankments on steep slopes, attention should be given to preventing a slippage plane.Benching is required in such locations (see Subsection 2.03-10.03). Where embankments 5 feet (1.5 meter) orless in height are to be constructed. The top 6 inches (150 millimeter) of the ground on which the embankmentis to be placed must be watered, processed, and compacted to 95% of maximum density in accordance with theStandard Specifications.Earth embankments should be constructed in successive layers, not more than 8 inches (200 millimeter) thickbefore compaction. Thinner layers usually compact more readily. Roots and other unsuitable material should beremoved before compaction. Layers of embankment on hillsides should be placed part width, beginning at thelow side and decreasing in width as the embankment is raised. Earth embankments are generally built withscraper type equipment that haul, spread, and compact the embankment material.Operators of large heavy equipment very rarely compact right to the outer edge of the embankment. They preferto travel in a compacted area away from the edge. This leaves an uncompacted area several feet wide. TheInspector should watch for these areas and other areas where large equipment cannot maneuver, and requiresupplemental compaction. If supplemental compaction is not provided, the Resident Engineer should beinformed and density tests should be taken in the uncompacted area.Construction Manual 203 - 13

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GRADING August 2009When embankment slopes are to be seeded, surface cultivation to the specified depth is critical for minimizingerosion and achieving favorable seed germination. A minimum tillage of 6 inch depth is required on fill slopesand a minimum tillage of 12 inch depth is required on cut slopes. The seeding contractor generally doesn’t havethe equipment to accomplish desired tillage. This is best achieved through the general contractor, who hasaccess to larger equipment. The soil should be left in a loose, evenly roughened condition, free of clods or largestones with the entire width of the tillage cultivated to the specified depth. This may require passing theequipment over the same area parallel to the contours several times to provide thorough soil cultivation. Alltillage should result in furrows no more than 12 inches apart and directional along the contours.Embankments should be constructed in such a manner that there will be no ponding of water that will soak intoand soften the lower levels of the embankment.Embankments can be constructed in cold weather, but the inspector must ensure no snow, or frozen chunks ofearth are placed in the embankment. Snow and ice will eventually melt and cause the embankment to settleunevenly.Changes in borrow placement that result in: • material with different properties, • substitution for excavated material, or • a change from a specified sourceare all changes to the contract and may require a supplemental agreement. Written approval is required tochange the borrow placement from that shown on the Project Plans.Subgrade FinishingAfter all approved materials have been incorporated into the subgrade and compacted to the required density,"blue top" grade stakes, wire control line, or another method approved by the engineer shall be used to providethe finished subgrade elevation. Before the placement of any further materials, the Inspector shall verify that theroadway has been trimmed or slight fills made to bring the subgrade to desired grade and section. The finalsubgrade density tests must be performed and tests made on the subgrade materials (PI and materials passinga #200 (75μm) sieve) before any base material is placed on the roadway.The subgrade is to be finished in conformity with the elevations called for in the Project Plans. When asphalt orconcrete pavements are placed directly on the subgrade, without select or aggregate base, it is very important toconstruct the subgrade to the proper cross slope and grade. Subgrade tolerances are shown in the StandardSpecifications.(B) Compaction(1) EarthIdeal conditions for obtaining compaction with the least effort would be a material that contains uniform moisturecontent near optimum. Often, maintaining the moisture slightly below optimum works better. With the use ofheavy rolling equipment, moisture at optimum or slightly above may cause the material to be unstable.Most soils compact more readily in thin layers. This is the reason for maximum lift requirements that appear inthe Standard Specifications. In some cases it may be in the Contractors interest to further reduce the liftthickness.Construction Manual 203 - 14

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GRADING August 2009Embankment placed near a bridge abutment must conform to special compaction requirements that will preventsettlement of approach slabs and anchor slabs.Prewetting of roadway excavation and borrow pits is common practice among Contractors: distribution of wateris usually better, dust is controlled, loading of scrapers is aided, and compaction can be obtained easily with aminimum of loss by evaporation. (See Subsection 206-3 for the method of computing the weight of materials towhich water has been added.)The amount of watering and rolling required in the construction of rock embankments depends on the amountand character of fine material contained between the rock fragments. Close observation of the placement of thematerial and good judgment will determine the amount of water and type of compaction needed. Normally, if thefine material does not fill the voids between the rocks, watering and rolling will not be effective. Sincecompaction tests can seldom be performed in rock embankments, the Inspector must give this type of work moreattention than normally required for other embankments.Stability and support of soils is directly affected by the degree of compaction. The lower the compaction, thelower the support, especially when moisture is present.As mentioned in the discussion of embankment, the Inspector should keep the Contractor advised of possibleproblem areas involving drainage and the roadway prism.Saturated areas are to be drained, dried out, and compacted before being covered. Sometimes it is moreefficient to just replace the material.Filling in with dry material is usually not an acceptable method of stabilizing wet earth because complete mixingof the wet and dry material seldom occurs. The mixed area will look stable and may temporarily supportconstruction equipment, but it will eventually fail under repeated loading.Do not allow the Contractor to bridge over a soft spot by covering the spot with dry, stable material. Soft,unstable areas do not meet specifications and must be corrected.The removed material can be wasted in areas outside the roadway prism, or if sufficient embankment isavailable, it can be spread out to dry in thin lifts. Before being placed within 3 feet (1 meter) of finished subgradeelevation, the material is to be tested to be sure it meets subgrade acceptance requirements.The Inspector needs to keep good records of the areas needing corrective work and how the work wasaccomplished.Soils will vary widely as to the amount of effort necessary to achieve a uniform degree of compaction. It is theContractors responsibility to provide the equipment needed to obtain the required density.Compaction tests should be performed so that they represent any area where it is suspected that there may beinadequate compaction (such as near outside edges of roadway or near structures). The outside edges of fillsshould be given extra attention to assure density. Each lift of material placed must be tested and approvedbefore placing additional lifts.The Contractor should be immediately advised of the results of the compaction tests.Construction Manual 203 - 15

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GRADING August 2009Testing equipment (such as "speedy" moisture testers, scales, molds, proctor hammers, nuclear gauges, andvolume measuring devices) is to be checked or recalibrated before the start of each project, and at suitableintervals during the life of the project.(2) RockRocky fill material should not be deposited in large piles and leveled off. Dumping the material on top of thelayer being built and shoving it ahead with a dozer can obtain a more uniform arrangement of the different rocksizes. This method will provide a more effective placement of the material in the fill so that there will be aminimum of voids. When possible, rock should be placed, spread, and leveled in 24 inch (0.6 meter) thicklayers. The ideal layer will cover the full width of embankment and contain sufficient earth or other fine materialto fill the interstices between rocks. The top layer of the rock embankment should be built with the most caresince this layer serves as the subgrade. Where suitable material is available within the cut area, it may be setaside for finishing the final layer. However, such material should be used only after tests have been performedto prove that its use is acceptable per Section 203-10. The use of material containing clay or frozen earth mustbe avoided for plating rocky subgrade. If satisfactory quality plating material is not available, it is better to use agreater thickness of subbase material for filling any irregularities in the surface of the subgrade.In rocky material the Inspector should seek out areas that can be tested. There is a tendency to easily dismissthe need for compactive effort simply because the material is rocky. Vibratory compaction is best for rocky soil,but almost any type of compactive effort will be beneficial.Construction Manual 203 - 16

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GRADING January 2005204 RESHAPING AND GRADING EXISTING IMPROVEMENTSUnder this section all work is performed that is necessary to modify or restore existing features (such asembankment slopes, dikes, ditches, medians, and other features). Finishing the subgrade or existing surfacingis not included under this section.The Project Plans are to be checked carefully to determine the extent of the work to be done under this section.A complete list of the work should be made to aid in tracking completed work and for the development of partialpayments.Construction Manual 204 - 1

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GRADING January 2005205 GRADING ROADWAY FOR PAVEMENT205-3 Construction RequirementsThe use of staged construction often makes it necessary to reshape a previously constructed subgrade or tomodify a design pavement structural section. The Contractor should scarify the entire road surface within theroadway prism, if necessary, and rebuild, recompact, remove, or reshape it to the cross-section shown on theProject Plans.The inspector should check the bid schedule to see if removals of existing concrete medians, curb and gutter, orother obstructions are included in payment for grading roadway for pavement.Shifting of material may be necessary in some cases and in others it may become necessary to import additionalmaterials. Complete and satisfactory compaction of the entire reshaped cross section must be achieved beforeplacement of base material.Where necessary, the surface material at approaches to structures shall be removed to a depth sufficient toallow the placement of the designed thickness of subbase, base, and pavement.205-3.04 Compacting and FinishingWhen asphaltic concrete or Portland cement concrete is to be placed directly on the subgrade, it will benecessary to finish the subgrade to specified tolerances. It may be necessary to import a select borrow materialto obtain the degree of finishing needed. Finishing tolerances are the same as for subgrade discussed inSection 203-10. The finish should be as uniform as possible. This prevents nonuniform compaction and theuneconomical use of paving materials to fill in low spots.Construction Manual 205 - 1

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GRADING April 2011206 FURNISH WATER SUPPLY 206­1 Description Furnishing a water supply is a lump sum item and consists of providing a water supply sufficient for the needs of the project including the hauling and applying of all water required in the compacting of embankment, base, and surfacing material, special backfill, and other fill and backfill. The “Furnish Water Supply” bid item should be used on remote projects where it is difficult to obtain water. The furnishing of all water required for the control of dust and any water used in wetting cuts and pits must be included in the “Furnish Water Supply” item. 206­3 Construction Requirements The inspector should check the Special Provisions for pre­wetting requirements when cuts are deeper than 3 feet (1 meter). The inspector should review subsection 206­3 of the Standard Specifications when the contractor decides to pre­wet pay items that will be measured and paid on the basis of weight – the specification’s intent is that the contractor be paid the weight of this material prior to pre­wetting. 206­5 Basis of Payment Generally payment for this item is made at the contract lump sum price. Occasionally, the Bidding Schedule omits “Furnish Water Supply” as a pay item. The Inspector should carefully review this item in the Standard Specifications and Special Provisions to ensure proper procedures are followed. Furnishing water for dust palliative and pre­wetting is included in payment for the items of work requiring water when the “Furnish Water Supply” pay item is omitted from the bid schedule.Construction Manual 206 ­ 1

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GRADING January 2005208 SEPARATION GEOTEXTILE FABRIC208-2 MaterialsA Certificate of Compliance must accompany all geotextile fabric delivered to the project. If the deliveredmaterials are not on the ADOT Materials Group pre-approved list, then the fabric must include a Certificate ofAnalysis along with supporting documentation. Each roll of fabric must be tagged, and the Engineer mustapprove each lot, or shipment before the materials are incorporated in the work.The inspector should ensure all requirements of Standard Specification and Special Provision sub sections 208-2 and 1014 are met. Particular attention must be given to protecting the fabric from sunlight since ultraviolet rayswill rapidly destroy the fabric.208-3 Construction RequirementsDetailed installation instructions are included in the Standard Specifications and Special Provisions. Additionalinstallation instructions should be available from the manufacturer or local supplier. The Resident Engineershould obtain and review this information before construction begins.Adequate anchoring is required to prevent haul trucks from pushing or shifting the fabric out of position. Alwaysback dump on the fabric and spread the material over the fabric. Dump subsequent loads onto the leveled fillmaterial and advance by spreading; do not mix material on the fabric.Should the fabric be damaged in any way during or after installation, it may be repaired by patching. Therecommended repair procedures are to remove the damaged area and place a piece of fabric of appropriatedimensions to cover the damaged area and extending 3 feet (1 meter) beyond in all directions.Construction Manual 208 - 1

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GRADING January 2005 REFERENCES AND ADDITIONAL INFORMATIONSection 200ADOT Erosion and Pollution Control Manual, Arizona Department of Transportation,Intermodal Transportation Division, Phoenix, AZSection 203The INSTITUTE OF MAKERS OF EXPLOSIVES (IME) is the safety association of thecommercial explosive industry in the United States and Canada. This non-profit,incorporated association is concerned primarily with safety in the manufacture,transportation, storage, handling, and use of explosive materials and other essentialapplications. The IME has a Safety Library comprised of publications pertaining to: 1. Construction Guide for Storage Magazines 2. American Table of Distances 3. Suggested Code of Regulations 4. Warnings and Instructions for Consumers in Transporting, Storing, Handling and Using Explosive Materials. 5. Handbook for the Transportation and Distribution of Explosive Materials 6. Safety in the Transportation, Storage, Handling and Use of Explosive Materials 7. Safety Guide for the Prevention of Radio Frequency Radiation Hazards in the Use of Commercial DetonatorsWorkbooks for Field Sampling and Testing for Earthwork (Course No. 101R), ArizonaDepartment of Transportation, Phoenix, AZWorkbook for Excavation and Embankment Inspection (Course No. 102), ArizonaDepartment of Transportation, Phoenix, AZWorkbook for Subgrade and Base Course Inspection (Course No. 104), ArizonaDepartment of Transportation, Phoenix, AZCaterpillar Performance HandbookConstruction Manual Chapter 2 References - 1